Frequently, when tubulars downhole degrade or are damaged a cut is made below the damaged portion. The upper portion of that string that could be hung off a larger tubular with a hanger is then removed from the well with the hanger. Tools are run in to remove the cement that was behind the removed tubular down to an area immediately surrounding the stub. Removal of the cement around the stub and dressing the exterior of the stub allows the replacement string of tubulars with an overshot fitting to be lowered down around the outside of the stub. Traditionally, these overshot fittings have included a soft metallic sealing material that was forced into specially made grooves in the inside diameter of the overshot fitting. The overshot would grab onto the casing stub and a pull would force the sealing material into the grooves and lock the two bodies together.
Other designs involved using an inflatable tool to expand the end of the stub into an overshot fitting with an interior configuration that included sealing material in grooves and a concave recess with serrations. Some examples of this design are U.S. Pat. Nos. 4,817,716 and 4,827,748. U.S. Pat. No. 4,648,626 also shows expansion using fluid pressure to urge a relatively softer metal into a surrounding tubular that has an irregular internal surface. A related design involves axially compressing a plug that is positioned within a stub until it deforms against a surrounding a flanged sleeve. This technique was used for repair for subsea pipelines. A related technique is described in U.S. Pat. No. 6,405,762 where pressure is used to expand the stub from within into a surrounding flanged sleeve with internal surface irregularities to promote grip. One issue with these techniques was control of the degree of expansion was difficult using the expansion techniques of applying hydraulic pressure or axially squeezing a plug to get it to move radially. Another issue is the unique application of some of these designs precludes their use downhole to connect to and seal against a casing stub, for example. Additionally these designs required sealing material to be displaced carefully into grooves and the connection to remain together with lock rings or due to surface irregularities and deformation of the stub into them from hydraulic expansion from within. Yet other techniques have been used to expand a patch into a tubular using a swage where the patch may have been fluted to reduce its diameter for insertion or the patch is simply expanded into contact with surrounding casing all at once or in stages. This type of art generally deals with inserting a patch in the middle of a casing string or hanging another string at the lower end of an existing string. Some examples of these approaches are U.S. Pat. Nos. 3,191,677; 6,142,230 and 6,561,271. Yet other designs for connecting tubulars require an initial flaring of the receiving tubular to accept another tubular that after insertion is deformed to put sealing bands into contact with the surrounding already flared tubular. This is illustrated in U.S. Pat. No. 5,095,991. In U.S. Pat. No. 6,585,053 a tubular string is inserted in a lager string and the top of the inner string is expanded pushing an exterior seal into the surrounding tubular. The tubular that was just inserted and expanded also presents a polished bore receptacle to receive yet another tubular string from the surface. U.S Application 2002/0195252 is similar.
What is needed and provided by the present invention is a technique and equipment that allows rapid connection to a stub downhole preferably using a swage and making a connection where the internal diameter is not reduced. Simple expansion techniques using a swage are employed to either expand the stub into an overshot connector. Another alternative technique inserts a tubular into the stub for tandem expansion and another variation involves insertion of a tubular end into the stub and an overshot component exterior to the stub to obtain and interior and exterior sealing on the stub. Optionally seals or surface irregularities can be employed to enhance sealing contact. These and other features of the present invention will be more readily apparent to those skilled in the art from a review of the description of the preferred embodiment, the drawings and the claims appended below.